@Kenneth Österberg Thanks for reaching out. All NonVNet Stv1 to Stv2 migrations are currently disabled.
This is due to a bug in APIM ResourceProvider. The fix is currently set to rollout on 06/08/2024.
We do understand that Teams have a rush to migrate within deadline and we apologies for the inconvenience caused. You can explore alternatives at https://aka.ms/apim-migrate-stv2
do let me know incase of further queries, I would be happy to assist you.
Please accept as Yes if the answer provided is useful, so that you can help others in the community looking for remediation for similar issues.